The ability to create layers when sculpting landscape, similar to Photoshop or Mudbox. For example, if I import dunes in from World Machine, I could have that on a layer, then make a new layer and start sculpting and making changes. I could make cliffs on the north side of the map as a layer, and a flat area in the middle of the map as a layer. Later on if I don’t like that cliff, I can delete the layer and be back to dunes. If I’d rather have the flat area more to the south, I could grab its layer and drag it south, then do some touching up to make it fit with that area.
I hate having to work destructively when it comes to landscape and this would help tremendously with large outdoor landscapes.